Enter the width and height of a rectangle and get its area, perimeter, diagonal length, and the angle the diagonal makes with the base — useful for construction, screens and displays, framing, flooring, and geometry homework.
How it works
The tool applies four standard formulas to the width (w) and height (h) you enter:
- Area = w × h
- Perimeter = 2 × (w + h)
- Diagonal = √(w² + h²) — the Pythagorean theorem, because the diagonal is the hypotenuse of the right triangle formed by the width and height
- Diagonal angle = arctan(h ÷ w), converted to degrees — the angle the diagonal makes with the base
It is unit-agnostic: use any unit consistently and the lengths come out in that unit, the area in square units, and the angle in degrees.
Example
For a rectangle 4 by 3:
- Area = 4 × 3 = 12
- Perimeter = 2 × (4 + 3) = 14
- Diagonal = √(4² + 3²) = √25 = 5
- Diagonal angle = arctan(3 ÷ 4) ≈ 36.87°
| Width | Height | Area | Perimeter | Diagonal |
|---|---|---|---|---|
| 4 | 3 | 12 | 14 | 5 |
| 16 | 9 | 144 | 50 | ~18.36 |
| 10 | 10 | 100 | 40 | ~14.14 |
All maths runs in your browser — nothing is uploaded.